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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Apache License, Version 2.0. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Apache License, Version 2.0, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Apache License, Version 2.0.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System.Collections.Generic;
#if SILVERLIGHT
using System.Core;
#endif
#if CLR2
namespace Microsoft.Scripting.Ast.Compiler {
#else
namespace System.Linq.Expressions.Compiler {
#endif
/// <summary>
/// A simple dictionary of queues, keyed off a particular type
/// This is useful for storing free lists of variables
/// </summary>
internal sealed class KeyedQueue<K, V> {
private readonly Dictionary<K, Queue<V>> _data;
internal KeyedQueue() {
_data = new Dictionary<K, Queue<V>>();
}
internal void Enqueue(K key, V value) {
Queue<V> queue;
if (!_data.TryGetValue(key, out queue)) {
_data.Add(key, queue = new Queue<V>());
}
queue.Enqueue(value);
}
internal V Dequeue(K key) {
Queue<V> queue;
if (!_data.TryGetValue(key, out queue)) {
throw Error.QueueEmpty();
}
V result = queue.Dequeue();
if (queue.Count == 0) {
_data.Remove(key);
}
return result;
}
internal bool TryDequeue(K key, out V value) {
Queue<V> queue;
if (_data.TryGetValue(key, out queue) && queue.Count > 0) {
value = queue.Dequeue();
if (queue.Count == 0) {
_data.Remove(key);
}
return true;
}
value = default(V);
return false;
}
internal V Peek(K key) {
Queue<V> queue;
if (!_data.TryGetValue(key, out queue)) {
throw Error.QueueEmpty();
}
return queue.Peek();
}
internal int GetCount(K key) {
Queue<V> queue;
if (!_data.TryGetValue(key, out queue)) {
return 0;
}
return queue.Count;
}
internal void Clear() {
_data.Clear();
}
}
}
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